easy:SetOpt_Proxy_PinnedPublicKey(pinnedpubkey)
When negotiating a TLS or SSL connection, the https proxy sends a certificate indicating its identity. A public key is extracted from this certificate and if it does not exactly match the public key provided to this option, curl will abort the connection before sending or receiving any data.
On mismatch, #CURLE_SSL_PINNEDPUBKEYNOTMATCH
is returned.